溶解氧对低碳源城市污水处理系统脱氮性能与微生物群落的影响

Effects of Dissolved Oxygen on Nutrient Removal Performance and Microbial Community in Low Carbon/Nitrogen Municipal Wastewater Treatment Process

为了阐明溶解氧对低碳源城市污水处理系统脱氮除磷性能的影响,研究了供氧区溶解氧浓度分别为2~3、1~2和低于1 mg·L^(-1)的运行条件下微生物应对低碳源环境生长与代谢特性的差异.随着供氧区溶解氧浓度的降低利用外碳源和内碳源脱氮量分别升高了20.23%和80.54%,内碳源的除磷利用效率升高了13.89%,进而使低碳源城市污水的脱氮除磷效果得到强化.高通量测序和RDA分析结果表明,降低供氧区溶解氧浓度驱动微生物群落结构的调整,促使脱氮除磷功能微生物(如:Dechloromonas菌属)的丰度显著增加.基于PICRUSt预测分析可知,在低溶解氧浓度的运行环境中微生物与基质利用、能量合成和代谢调控功能相关的基因活性更高,保证了功能微生物在低碳源条件下稳定生长并维持较高的脱氮除磷效率.本研究为提升低碳源城市污水处理系统中脱氮除磷功能微生物的生长提供理论依据.

To explore the effects of dissolved oxygen( DO) on the treatment of low carbon/nitrogen municipal wastewater,this study examined the characteristics of the microbial community in a low carbon source environment. The treatment process was conducted with the aeration area having DO concentrations of 2-3,1-2,and lower than 1 mg·L^(-1). The results demonstrated that reduced DO concentration in the aeration area increased the efficiency of the nitrogen removal process by 20. 23% and 80. 54%,for external and internal carbon sources,respectively. Similarly,the efficiency of internal carbon source utilization in the phosphorus removal process increased by 13. 89%,thus enhancing the nutrient removal efficiency of the low carbon/nitrogen wastewater treatment system. Highthroughput sequencing and RDA analysis showed that reduced oxygen concentration motivated an adjustment in microbial community structure,causing functional microorganisms( i. e.,Dechloromonas) to become dominant. In addition,the upregulation of genes associated with energy production and conversion,signal transduction,substrate transport,and metabolism provided favourable nutritional conditions for the proliferation of functional microorganisms in low carbon source conditions. This study provides a theoretical basis for improving the growth of microorganisms involved in the nutrient removal process when treating low carbon/nitrogen municipal wastewater.